The present invention relates to automatic mechanical transmissions (AMT) of vehicles and more specifically, to an automatic manual transmission gear shift assembly including a timed shift delay for vehicles such as tractor trailers, heavy duty trucks, buses and the like.
Automatic mechanical transmissions of the stage-geared gearbox type have become increasingly common in tractor trailers and heavy-duty vehicles as microcomputer technology has continued to advance and has made it possible, with a control computer and a number of control elements, e.g., servo motors, to precision-control the engine speed, the connection and disconnection of an automated clutch between engine and gearbox, and coupling members of the gearbox, relative to one another, so that smooth gearshifts are obtained at the correct speeds. The advantage of these types of automatic gearboxes, when compared with traditional automatic gearboxes constructed with planetary gear steps and with hydrodynamic torque converters on the input side, is that first, such devices are simpler, more robust, and can be produced at substantially lower costs than the traditional automatic gearboxes, and second, the gearboxes have greater efficiencies, meaning lower fuel consumption for the incorporating vehicle. Typically, control of these gearboxes is provided by means of a gear shifting selector electronically linked to the gearbox.
A known solution uses a gear selector that is fixed to the seat. On the side of the selector facing the driver's seat is a +/− button, in a toggle-type switch configuration, with up and down spring back positions, as well as a neutral position in the middle. Besides the toggle-type switch configuration which is shown, it is also contemplated that among other designs, a configuration using two distinct +/− push buttons may be utilized.
As shown, on top of the gear selector is a button that is used to tilt the gear selector to the horizontal position. On the front is a gear selector lock which must be pressed in order to change the gears from neutral to reverse, neutral to drive and manual to “limp home”.
The gear selector may also be used to choose between a number of different driving programs including, but not limited to reverse, neutral, automatic, manual, economy, power, and the like. When in the automatic and manual programs, the operator of the vehicle may select a desired gear by pressing the +/− button of the selector and the +/− button may be used to change gears one step at a time during manual gear changing, manually change a gear one step when in automatic gear changing, manually change a gear one step when in neutral.
While there are many other advantageous features of the known solution gear selector, one problem is that it does not allow an operator to skip between gears. That is, if an operator desires to shift between nonconsecutive gears, for example, from third gear to fifth gear, the operator must press the +/− button twice. After the +/− button is pressed the first time, the gear shift automatically begins to direct the gearbox to shift to fourth gear and after the +/− button is pressed the second time, the gearbox is then directed to shift to fifth gear. This is problematic because the first gear shift request must be interrupted by the second gear request and can cause gearshift delay and generally result in an undesirable gearshift transition.
The present invention recognizes the need for an electronic gear shift selector that allows an operator to skip directly between non-consecutive gears without having to interrupt a first gear shift request.
In at least one embodiment, the present invention takes the form of an electronic gear shift selector toggle switch, or button, that includes a counter and time delay circuit to allow an operator to shift directly between non-consecutive gears. The shift is implemented once the time delay circuit determines that the appropriate period of time has passed since the last activation of the toggle switch. The system detects, and a counter registers (counts) the number of times the toggle switch is asserted and the time delay circuit is configured to delay the communication of the number of assertions until a predetermined period of time has lapsed. The counter is preferably software based, but it is also contemplated that the counter may be a hardware based counter of known design. In one embodiment, the time delay circuit delays communication of the number of assertions between 0.3 and 1 second after the toggle switch is first asserted. In another embodiment, if a second assertion is detected within a predetermined time period, the time delay circuit is reset and communication of the number of assertions is delayed a further period of between 0.1 and 0.5 second thereafter.
In still yet another embodiment, assertion of the toggle switch a predetermined number of times, holding the toggle switch in the asserted position, or combinations thereof can be used to cancel a gear shift request. Similarly, assertion of the toggle switch a predetermined number of times, holding the toggle switch in the asserted position, or combinations thereof can be used to automatically cycle through the gears without having to continually individually assert the toggle switch to cycle through gears. This feature, in a preferred embodiment, displays the selected gear on a driver display and allows the driver to select the desired gear directly. Additionally, the selection of a particular gear is relayed to the driver through an audible signal. In a preferred embodiment, the selection of a particular gear is limited so as to prevent engine overspeed or lugging. Another embodiment is when the + side of the toggle switch is depressed in such a fashion that it causes the transmission to shift to the highest gear, and when the − side of the toggle switch is depressed in such a fashion that it causes the transmission to shift to the lowest gear.